K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
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K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
 
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With minor circuit changes, both the K3's speaker amplifier and line
outputs can provide lower IMD (intermodulation distortion) at higher signal levels. We've been testing these changes for a couple of months, and have already phased them into production. These changes can easily be made to existing K3s. A kit of parts is available (K3AFMDKT). All parts are leaded (not surface mount), and full instructions are provided. See: http://www.elecraft.com/order_form_parts.htm#K3%20Parts Details ------- SPEAKER AMP: The mod kit includes a very low-resistance RF choke for use at RFC47 on the RF board. This improves speaker amplifier IMD by as much as 25 dB at moderate to high AF GAIN settings by reducing the voltage drop across RFC47 during signal peaks. LINE OUT: The kit also includes smaller resistor values for R19 and R20 on the KIO3 module. At present R19 and R20 are about 600 ohms, while the replacements drop the resistance to around 50 ohms. The smaller resistors increase the available voltage swing at the output of the LINE OUT transformers, which improves IMD at higher signal levels. These two changes are independent. For example, if you never use LINE OUTs, you might want to do only the speaker amp modification. 73, Wayne N6KR --- http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Wayne
Can you tell us the serial number at which these changes were incorporated? We need to know who needs to order them and who does not. Thanks and 73 Bob N6WG ----- Original Message ----- From: "wayne burdick" <[hidden email]> To: "Elecraft Reflector" <[hidden email]> Sent: Thursday, November 13, 2008 10:40 AM Subject: [Elecraft] K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs) > With minor circuit changes, both the K3's speaker amplifier and line > outputs can provide lower IMD (intermodulation distortion) at higher > signal levels. We've been testing these changes for a couple of months, > and have already phased them into production. > > These changes can easily be made to existing K3s. A kit of parts is > available (K3AFMDKT). All parts are leaded (not surface mount), and > full instructions are provided. See: > > http://www.elecraft.com/order_form_parts.htm#K3%20Parts > > Details > ------- > > SPEAKER AMP: The mod kit includes a very low-resistance RF choke for > use at RFC47 on the RF board. This improves speaker amplifier IMD by as > much as 25 dB at moderate to high AF GAIN settings by reducing the > voltage drop across RFC47 during signal peaks. > > LINE OUT: The kit also includes smaller resistor values for R19 and > R20 on the KIO3 module. At present R19 and R20 are about 600 ohms, > while the replacements drop the resistance to around 50 ohms. The > smaller resistors increase the available voltage swing at the output of > the LINE OUT transformers, which improves IMD at higher signal levels. > > These two changes are independent. For example, if you never use LINE > OUTs, you might want to do only the speaker amp modification. > > 73, > Wayne > N6KR > > --- > > http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
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I would also like to know that please.
73, Igor UA9CDC > Wayne > Can you tell us the serial number at which > these changes were incorporated? > We need to know who needs to order them > and who does not. > Thanks and 73 > Bob N6WG > > ----- Original Message ----- > From: "wayne burdick" <[hidden email]> > To: "Elecraft Reflector" <[hidden email]> > Sent: Thursday, November 13, 2008 10:40 AM > Subject: [Elecraft] K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs) > > >> With minor circuit changes, both the K3's speaker amplifier and line >> outputs can provide lower IMD (intermodulation distortion) at higher >> signal levels. We've been testing these changes for a couple of months, >> and have already phased them into production. >> >> These changes can easily be made to existing K3s. A kit of parts is >> available (K3AFMDKT). All parts are leaded (not surface mount), and full >> instructions are provided. See: >> >> http://www.elecraft.com/order_form_parts.htm#K3%20Parts >> >> Details >> ------- >> >> SPEAKER AMP: The mod kit includes a very low-resistance RF choke for use >> at RFC47 on the RF board. This improves speaker amplifier IMD by as much >> as 25 dB at moderate to high AF GAIN settings by reducing the voltage drop >> across RFC47 during signal peaks. >> >> LINE OUT: The kit also includes smaller resistor values for R19 and R20 >> on the KIO3 module. At present R19 and R20 are about 600 ohms, while the >> replacements drop the resistance to around 50 ohms. The smaller resistors >> increase the available voltage swing at the output of the LINE OUT >> transformers, which improves IMD at higher signal levels. >> >> These two changes are independent. For example, if you never use LINE >> OUTs, you might want to do only the speaker amp modification. >> >> 73, >> Wayne >> N6KR >> >> --- >> >> http://www.elecraft.com >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft Help: >> http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
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In reply to this post by wayne burdick
wayne burdick wrote:
> > SPEAKER AMP: The mod kit includes a very low-resistance RF choke for > use at RFC47 > 73, > Wayne > N6KR > What is the value? / SM2EKM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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> wayne burdick wrote:
>> >> SPEAKER AMP: The mod kit includes a very low-resistance RF choke for >> use at RFC47 >> 73, >> Wayne >> N6KR >> > What is the value? / SM2EKM Could this be homebrewed? Core, turns, wire? / LZ1VB _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
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Administrator
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In reply to this post by wayne burdick
This information and a mod manual are now on our K3 Enhancements and
Applications note page. See: http://www.elecraft.com/K3/k3_app_notes.htm I apologize for the delay getting this posted! It should have been up earlier. >From that page: Line-Out KIO3 R19/R20 Change: About Oct 7, 2008 About S/N 1900 Speaker Amp RFC47 Change: About Sept 25, 2008 About S/N 1830 (Dates and serial numbers are approximate and may vary slightly.) 73, Eric WA6HHQ ------ N6WG wrote: > I would also like to know that please. > 73, Igor UA9CDC > >> Wayne >> Can you tell us the serial number at which >> these changes were incorporated? >> We need to know who needs to order them >> and who does not. >> Thanks and 73 >> Bob N6WG >> >> ----- Original Message ----- From: "wayne burdick" <[hidden email]> >> To: "Elecraft Reflector" <[hidden email]> >> Sent: Thursday, November 13, 2008 10:40 AM >> Subject: [Elecraft] K3 AF Upgrade Kit (for speaker amplifier and LINE >> OUTs) >> >> >>> With minor circuit changes, both the K3's speaker amplifier and line >>> outputs can provide lower IMD (intermodulation distortion) at higher >>> signal levels. We've been testing these changes for a couple of >>> months, and have already phased them into production. >>> >>> These changes can easily be made to existing K3s. A kit of parts is >>> available (K3AFMDKT). All parts are leaded (not surface mount), and >>> full instructions are provided. See: >>> >>> http://www.elecraft.com/order_form_parts.htm#K3%20Parts >>> >>> Details >>> ------- >>> >>> SPEAKER AMP: The mod kit includes a very low-resistance RF choke >>> for use at RFC47 on the RF board. This improves speaker amplifier >>> IMD by as much as 25 dB at moderate to high AF GAIN settings by >>> reducing the voltage drop across RFC47 during signal peaks. >>> >>> LINE OUT: The kit also includes smaller resistor values for R19 and >>> R20 on the KIO3 module. At present R19 and R20 are about 600 ohms, >>> while the replacements drop the resistance to around 50 ohms. The >>> smaller resistors increase the available voltage swing at the output >>> of the LINE OUT transformers, which improves IMD at higher signal >>> levels. >>> >>> These two changes are independent. For example, if you never use >>> LINE OUTs, you might want to do only the speaker amp modification. >>> >>> 73, >>> Wayne >>> N6KR wayne burdick wrote: > With minor circuit changes, both the K3's speaker amplifier and line > outputs can provide lower IMD (intermodulation distortion) at higher > signal levels. We've been testing these changes for a couple of > months, and have already phased them into production. > > These changes can easily be made to existing K3s. A kit of parts is > available (K3AFMDKT). All parts are leaded (not surface mount), and > full instructions are provided. See: > > http://www.elecraft.com/order_form_parts.htm#K3%20Parts > > Details > ------- > > SPEAKER AMP: The mod kit includes a very low-resistance RF choke for > use at RFC47 on the RF board. This improves speaker amplifier IMD by > as much as 25 dB at moderate to high AF GAIN settings by reducing the > voltage drop across RFC47 during signal peaks. > > LINE OUT: The kit also includes smaller resistor values for R19 and > R20 on the KIO3 module. At present R19 and R20 are about 600 ohms, > while the replacements drop the resistance to around 50 ohms. The > smaller resistors increase the available voltage swing at the output > of the LINE OUT transformers, which improves IMD at higher signal levels. > > These two changes are independent. For example, if you never use LINE > OUTs, you might want to do only the speaker amp modification. > > 73, > Wayne > N6KR > > --- > > http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Val-12
Hi,
I am a little confused as to exactly what is affected by the choke mod (the document only mentions "speakers"): Internal speaker? External speakers? Front panel headphones? Rear panel headphones? I am asking because I use headphones 99% of the time (currently front connected, but I am considering a move to the back) and because the russian testers explicitly said they were using the front headphone outputs. Knut - AB2TC
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> I am a little confused as to exactly what is affected by the choke mod (the
> document only mentions "speakers"): The document is accurate. It means the speaker amplifier, which is used to drive the internal speaker and the external speaker jack. Not the headphones or LINE OUT, just the speakers. There is a separate stereo amplifier which drives the headphones. Front and rear headphone jacks are driven from the same headphone amplifier. These jacks are driven only by this amplifier. There is a separate path not using the speaker amplifier or headphone amplifier that drives the LINE OUT, and only the LINE OUT. 73, Lyle KK7P _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Speaker amplifier modification:
In the AF stage upgrade instruction page 1 it is mentioned: “This mod changes RFC 47, 100 µH radio frequency choke that supplies power to the K3 audio amplifier. The original choke has a resistance of about 1.5 ohms. This resistance is high enough to cause some clipping of the audio signal at moderate volume settings, resulting in distortion products about 40 dB down. Replacing this choke with a physically larger unit with a resistance of about 0.2 ohms results in a 20 to 30 dB reduction in most distortion products” On the K3 circuit diagram RFC47 is marked with a value of 10uH. I plan to buy this choke locally “because the high shipping charges for the kit to Switzerland”. Which value is now correct 10uH or 100uH? 73 Willy HB9WI |
Re: K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
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As previously discussed, the replacement RFC in question is a 100 uH (not 10
uH) Bourns (old J.W. Miller) part number 5800-101-RC. Whether the old RFC is depicted on the schematic as 10 uH or 100 uH is immaterial as far as the mod is concerned. What's called for in the replacement procedure is the 100 uH choke. http://www.bourns.com/pdfs/5800_series.pdf Paul, W9AC ----- Original Message ----- From: "hb9wi" <[hidden email]> To: <[hidden email]> Sent: Thursday, November 20, 2008 1:51 PM Subject: Re: [Elecraft] K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs) Speaker amplifier modification: In the AF stage upgrade instruction page 1 it is mentioned: “This mod changes RFC 47, 100 µH radio frequency choke that supplies power to the K3 audio amplifier. The original choke has a resistance of about 1.5 ohms. This resistance is high enough to cause some clipping of the audio signal at moderate volume settings, resulting in distortion products about 40 dB down. Replacing this choke with a physically larger unit with a resistance of about 0.2 ohms results in a 20 to 30 dB reduction in most distortion products” On the K3 circuit diagram RFC47 is marked with a value of 10uH. I plan to buy this choke locally “because the high shipping charges for the kit to Switzerland”. Which value is now correct 10uH or 100uH? 73 Willy HB9WI -- View this message in context: http://n2.nabble.com/K3-AF-Upgrade-Kit-%28for-speaker-amplifier-and-LINE-OUTs%29-tp1495036p1558365.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K3 AF Upgrade Kit (for speaker amplifier and LINE OUTs)
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In reply to this post by Eric Swartz - WA6HHQ
I installed this last night in K3#51. I'm running uC 2.67, which
features the AGC-OFF hearing protection. I'm trying to decide what LINE OUT and AGC setting to use for digital modes with. If AGC is disabled, line out values 0, 1, 2, 3, and 4 produce strong differences. After that I see almost no change in output. If AGC is enabled, even moderate signals produce enough AGC action (even if AGC threshold is pegged) so that I need LINE OUT of 30 or so to get enough output. For now I get the best results in data modes with AGC OFF and a LINE OUT level of 5. Leigh/WA5ZNU > This information and a mod manual are now on our K3 Enhancements and > Applications note page. See: > > http://www.elecraft.com/K3/k3_app_notes.htm > > I apologize for the delay getting this posted! It should have been up > earlier. > > >From that page: > > Line-Out KIO3 R19/R20 Change: > About Oct 7, 2008 > About S/N 1900 > > Speaker Amp RFC47 Change: > About Sept 25, 2008 > About S/N 1830 > > (Dates and serial numbers are approximate and may vary slightly.) > > 73, Eric WA6HHQ > ------ > > N6WG wrote: > > I would also like to know that please. > > 73, Igor UA9CDC > > > >> Wayne > >> Can you tell us the serial number at which > >> these changes were incorporated? > >> We need to know who needs to order them > >> and who does not. > >> Thanks and 73 > >> Bob N6WG > >> > >> ----- Original Message ----- From: "wayne burdick" <[hidden email]> > >> To: "Elecraft Reflector" <[hidden email]> > >> Sent: Thursday, November 13, 2008 10:40 AM > >> Subject: [Elecraft] K3 AF Upgrade Kit (for speaker amplifier and LINE > >> OUTs) > >> > >> > >>> With minor circuit changes, both the K3's speaker amplifier and line > >>> outputs can provide lower IMD (intermodulation distortion) at higher > >>> signal levels. We've been testing these changes for a couple of > >>> months, and have already phased them into production. > >>> > >>> These changes can easily be made to existing K3s. A kit of parts is > >>> available (K3AFMDKT). All parts are leaded (not surface mount), and > >>> full instructions are provided. See: > >>> > >>> http://www.elecraft.com/order_form_parts.htm#K3%20Parts > >>> > >>> Details > >>> ------- > >>> > >>> SPEAKER AMP: The mod kit includes a very low-resistance RF choke > >>> for use at RFC47 on the RF board. This improves speaker amplifier > >>> IMD by as much as 25 dB at moderate to high AF GAIN settings by > >>> reducing the voltage drop across RFC47 during signal peaks. > >>> > >>> LINE OUT: The kit also includes smaller resistor values for R19 and > >>> R20 on the KIO3 module. At present R19 and R20 are about 600 ohms, > >>> while the replacements drop the resistance to around 50 ohms. The > >>> smaller resistors increase the available voltage swing at the output > >>> of the LINE OUT transformers, which improves IMD at higher signal > >>> levels. > >>> > >>> These two changes are independent. For example, if you never use > >>> LINE OUTs, you might want to do only the speaker amp modification. > >>> > >>> 73, > >>> Wayne > >>> N6KR > > > wayne burdick wrote: >> With minor circuit changes, both the K3's speaker amplifier and line >> outputs can provide lower IMD (intermodulation distortion) at higher >> signal levels. We've been testing these changes for a couple of >> months, and have already phased them into production. >> >> These changes can easily be made to existing K3s. A kit of parts is >> available (K3AFMDKT). All parts are leaded (not surface mount), and >> full instructions are provided. See: >> >> http://www.elecraft.com/order_form_parts.htm#K3%20Parts >> >> Details >> ------- >> >> SPEAKER AMP: The mod kit includes a very low-resistance RF choke for >> use at RFC47 on the RF board. This improves speaker amplifier IMD by >> as much as 25 dB at moderate to high AF GAIN settings by reducing the >> voltage drop across RFC47 during signal peaks. >> >> LINE OUT: The kit also includes smaller resistor values for R19 and >> R20 on the KIO3 module. At present R19 and R20 are about 600 ohms, >> while the replacements drop the resistance to around 50 ohms. The >> smaller resistors increase the available voltage swing at the output >> of the LINE OUT transformers, which improves IMD at higher signal >> levels. >> >> These two changes are independent. For example, if you never use LINE >> OUTs, you might want to do only the speaker amp modification. >> >> 73, >> Wayne >> N6KR >> >> --- >> >> http://www.elecraft.com >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft Help: >> http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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